The current study proposes to use a randomized controlled design to test the feasibility and impact of aerobic physical activity for children with Attention Deficit Hyperactivity (ADHD) and Disruptive Behavior Disorders (DBD) living in an urban poor community. Epidemiological studies estimate the community prevalence of ADHD to be between 8 and 23%, and DBD to be between 5% and 9%. The disorders are highly comorbid and rates are reported to be nearly three times higher among African American and urban poor communities where the resources available to meet the need are severely limited. If untreated, children with ADHD and DBD are likely to suffer long-term impairments across multiple domains. Evidence-based interventions for ADHD and DBD are psychopharmacological and psychosocial. Though both are effective, some children are unresponsive to or experience unwanted side effects from medications, and psychosocial treatments require considerable time and resources. Schools provide 70-80% of psychosocial services and the unfortunate reality in low-income schools is that limited resources, deteriorating conditions, high staff stress, and pressure to improve standardized test scores make the time and resource investments associated with mental health consultation and program implementation especially challenging. Consequently, rates of service utilization are extremely low in urban poor communities. This study builds on a sizeable literature demonstrating that ADHD is characterized by, and DBD has been associated with, impairments in the development of EF; and that aerobic activity disproportionately influences EF processes and the brain areas that support them. This evidence, coupled with the great need for development of evidence-based interventions for childhood ADHD and DBD that improve daily functioning, are low cost, and have potential for broad dissemination suggests that aerobic activity warrants investigation as a potential tool in the broad treatment and management of ADHD and DBD in urban poor communities. The proposed study will randomize children with ADHD and/or DBD to Project Play, an evidence-based 12-week after-school aerobic activity intervention demonstrated to improve EF in overweight non-disruptive children, or an attention control condition. It aims to (1) test the feasibility of Project Play for children with ADHD and DBD living in a high poverty community via attendance records, retention rates, and Heart Rate Monitoring; (2) examine whether the EF benefits of aerobic activity apply to children with ADHD and DBD via the Behavioral Rating Inventory of Executive Function and neuropsychological tasks; and (3) determine the extent to which the intervention influences children's behavior and academic performance via teacher-report, parent-report, direct observation, and curriculum-based measures. The current study will launch a program of research examining physical activity interventions as one component of coordinated mental health promotion efforts in urban poor communities.